reverse path forward (Routing) (RPF)

Reverse Path Forward (RPF) is a technique for forwarding multicast datagrams. In the RPF method, the router that receives the data packets remembers the data source and the interface through which the data was received. If the interface has the shortest path to the data source, the packets are forwarded to all other interfaces of the router. This does not require any specific multicast routing information. RPF defines a separate multicast tree for each sender, with only distance as a metric.

RPF has some advantages over flooding in terms of overhead and additional network load.